Alpha-1-antitrypsin deficiency. High prevalence in the St. Louis area determined by direct population screening

Precision Approaches to Chronic Obstructive Pulmonary Disease Management

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. COPD heterogeneity has hampered progress in developing pharmacotherapies that affect disease progression. This issue can be addressed by precision medicine approaches, which focus on understanding an individual's disease risk, and tailoring management based on pathobiology, environmental exposures, and psychosocial issues. There is an urgent need to identify COPD patients at high risk for poor outcomes and to understand at a mechanistic level why certain individuals are at high risk. Genetics, omics, and network analytic techniques have started to dissect COPD heterogeneity and identify patients with specific pathobiology. Drug repurposing approaches based on biomarkers of specific inflammatory processes (i.e., type 2 inflammation) are promising. As larger data sets, additional omics, and new analytical approaches become available, there will be enormous opportunities to identify high-risk individuals and treat COPD patients based on their specific pathophysiological derangements. These approaches show great promise for risk stratification, early intervention, drug repurposing, and developing novel therapeutic approaches for COPD.

Testing Alpha-1 Antitrypsin Deficiency in Black Populations

Alpha-1 antitrypsin (AAT) deficiency (AATD) is an under-recognized hereditary disorder and a significant cause of chronic obstructive pulmonary disease (COPD), a disease that contributes to global mortality. AAT is encoded by the SERPINA1 gene, and severe mutation variants of this gene increase the risk of developing COPD. AATD is more frequently screened for in non-Hispanic White populations. However, AATD is also observed in other ethnic groups and very few studies have documented the mutation frequency in these other ethnic populations. Here, we review the current literature on AATD and allele frequency primarily in Black populations and discuss the possible clinical outcomes of low screening rates in a population that experiences poor health outcomes and whether the low frequency of AATD is related to a lack of screening in this population or a truly low frequency of mutations causing AATD. This review also outlines the harmful SERPINA1 variants, the current epidemiology knowledge of AATD, health inequity in Black populations, AATD prevalence in Black populations, the clinical implications of low screening of AATD in this population, and the possible dangers of not diagnosing or treating AATD.

A Novel Provider Education Module to Enhance Detection of Alpha-1 Antitrypsin Deficiency

Background

Alpha-1 antitrypsin deficiency (AATD) is the most common genetic risk factor for early-onset emphysema. However, AATD continues to be underrecognized and underdiagnosed. Provider awareness about AATD, concerns with testing costs, and limited understanding about therapeutic options contribute to its underdiagnosis. We hypothesized that provider education would improve awareness of AATD and improve screening.

Objective

To evaluate the impact of a targeted provider education module on AATD screening.

Methods

We developed a web-based education module to address barriers to screening for AATD, deployed the education module using the Medscape Education platform, assessed perceived healthcare provider confidence in AATD screening, and conducted a prospective pre and postintervention study of AATD testing practices at a high-volume academic outpatient subspecialty pulmonary clinic.

Results

A total of 11,385 healthcare providers, including eight pulmonologists at our institution, completed the web-based education module. Confidence in identifying patients at high risk for AATD improved after completing the module ("not confident" in AATD screening was 7.7% postintervention compared with 19.4% preintervention). The rate of screening patients at high risk for AATD improved more than twofold (AATD screening rate 9.7% preintervention vs. 20.4% postintervention; P = 0.004). Among patients screened for AATD in our cohort, 27.2% had a genotype/phenotype or low alpha-1 antitrypsin concentration consistent with AATD.

Conclusion

Targeted healthcare provider education can improve the confidence in testing for AATD. Improvements in provider confidence corresponded to improvements in AATD screening in a subspecialty pulmonary clinic. More than one-fourth of screening tests suggested AATD, underpinning the value of testing in high-risk individuals.

Testing Patterns and Disparities for Alpha-1 Antitrypsin Deficiency

BACKGROUND

Alpha-1 antitrypsin deficiency is an under-recognized genetic cause of chronic lung and liver disease; it remains unclear what the testing frequency and disparities are for alpha-1 antitrypsin deficiency.

METHODS

This is a retrospective cohort study of people with newly diagnosed chronic obstructive pulmonary disease and liver disease identified at the University of Florida between January 1, 2012 and December 31, 2021. We performed incidence and prevalence analysis for alpha-1 antitrypsin (AAT) testing and point-biserial correlation analysis for tobacco use and AAT testing. We evaluated characteristics with AAT testing using adjusted multivariable logistic regression.

RESULTS

Among 75,810 subjects with newly diagnosed chronic obstructive pulmonary disease and liver disease between 2012 and 2021, 4248 (5.6%) were tested for AAT deficiency. All subjects had an AAT level performed, while 1654 (39%) had phenotype testing. Annual incidence of testing increased for subjects with newly diagnosed chronic obstructive pulmonary disease or liver disease from 2.8% and 5.4%, respectively, in 2012 to 4.1% and 11.3%, respectively, in 2021. Adjusted multivariable regression analysis showed factors favoring AAT testing were White race, and concomitant chronic obstructive pulmonary disease and liver disease. Increasing age, non-White race, current tobacco use, and being a male with chronic obstructive pulmonary disease had lower odds of AAT testing.

CONCLUSION

Although slowly improving, testing for AAT deficiency continues to have a low uptake in the clinical setting despite guidelines recommending broader testing. Individuals of White race and those with concomitant chronic obstructive pulmonary disease and liver disease are more likely to be tested, while older subjects, individuals of non-White race, current tobacco use, and men with chronic obstructive pulmonary disease are less favored to be tested.

Population genetic testing and SERPINA1 sequencing identifies unidentified alpha-1 antitrypsin deficiency alleles and gene-environment interaction with hepatitis C infection

Alpha-1 antitrypsin deficiency (AATD), a relatively common autosomal recessive genetic disorder, is underdiagnosed in symptomatic individuals. We sought to compare the risk of liver transplantation associated with hepatitis C infection with AATD heterozygotes and homozygotes and determine if SERPINA1 sequencing would identify undiagnosed AATD. We performed a retrospective cohort study in a deidentified Electronic Health Record (EHR)-linked DNA biobank with 72,027 individuals genotyped for the M, Z, and S alleles in SERPINA1. We investigated liver transplantation frequency by genotype group and compared with hepatitis C infection. We performed SERPINA1 sequencing in carriers of pathogenic AATD alleles who underwent liver transplantation. Liver transplantation was associated with the Z allele (ZZ: odds ratio [OR] = 1.31, p<2e-16; MZ: OR = 1.02, p = 1.2e-13) and with hepatitis C (OR = 1.20, p<2e-16). For liver transplantation, there was a significant interaction between genotype and hepatitis C (ZZ: interaction OR = 1.23, p = 4.7e-4; MZ: interaction OR = 1.11, p = 6.9e-13). Sequencing uncovered a second, rare, pathogenic SERPINA1 variant in six of 133 individuals with liver transplants and without hepatitis C. Liver transplantation was more common in individuals with AATD risk alleles (including heterozygotes), and AATD and hepatitis C demonstrated evidence of a gene-environment interaction in relation to liver transplantation. The current AATD screening strategy may miss diagnoses whereas SERPINA1 sequencing may increase diagnostic yield for AATD, stratify risk for liver disease, and inform clinical management for individuals with AATD risk alleles and liver disease risk factors.

COVID-19's impact on care practice for alpha-1-antitrypsin deficiency patients

BACKGROUND

Patients with alpha-1 antitrypsin deficiency (AATD), commonly categorized as a rare disease, have been affected by the changes in healthcare management brought about by COVID-19. This study's aim was to identify the changes that have taken place in AATD patient care as a result of the COVID-19 pandemic in Spain and to propose experts' recommendations aimed at ensuring humanized and quality care for people with AATD in the post-pandemic situation.

METHODS

A qualitative descriptive case study with a holistic single-case design was conducted, using focus groups with experts in AATD clinical management, including 15 health professionals with ties to the Spanish health system (12 pneumologists and 2 hospital pharmacists from 11 different hospitals in Spain) and 1 patient representative.

RESULTS

COVID-19 has had a major impact on numerous aspects of AATD clinical patient management in Spain, including diagnostic, treatment, and follow-up phases. The experts concluded that there is a need to strengthen coordination between Primary Care and Hospital Care and improve the coordination processes across all the organizations and actors involved in the healthcare system. Regarding telemedicine and telecare, experts have concluded that it is necessary to promote this methodology and to develop protocols and training programs. Experts have recommended developing personalized and precision medicine, and patient participation in decision-making, promoting self-care and patient autonomy to optimize their healthcare and improve their quality of life. The possibility of monitoring and treating AATD patients from home has also been proposed by experts. Another result of the study was the recommendation of the need to ensure that plasma donations are made on a regular basis by a sufficient number of healthy individuals.

CONCLUSION

The study advances knowledge by highlighting the challenges faced by health professionals and changes in AATD patient management in the context of the COVID-19 pandemic. It also proposes experts' recommendations aimed at ensuring humanized and quality care for people with AATD in the post-pandemic situation. This work could serve as a reference study for physicians on their daily clinical practice with AATD patients and may also provide guidance on the changes to be put in place for the post-pandemic situation.

Abnormal liver enzymes: A review for clinicians

Liver biochemical tests are some of the most commonly ordered routine tests in the inpatient and outpatient setting, especially with the automatization of testing in this technological era. These tests include aminotransferases, alkaline phosphatase, gamma-glutamyl transferase, bilirubin, albumin, prothrombin time and international normalized ratio (INR). Abnormal liver biochemical tests can be categorized based on the pattern and the magnitude of aminotransferases elevation. Generally, abnormalities in aminotransferases can be classified into a hepatocellular pattern or cholestatic pattern and can be further sub-classified based on the magnitude of aminotransferase elevation to mild [< 5 × upper limit of normal (ULN)], moderate (> 5-< 15 × ULN) and severe (> 15 × ULN). Hepatocellular pattern causes include but are not limited to; non-alcoholic fatty liver disease/non-alcoholic steatohepatitis, alcohol use, chronic viral hepatitis, liver cirrhosis (variable), autoimmune hepatitis, hemochromatosis, Wilson’s disease, alpha-1 antitrypsin deficiency, celiac disease, medication-induced and ischemic hepatitis. Cholestatic pattern causes include but is not limited to; biliary pathology (obstruction, autoimmune), other conditions with hyperbilirubinemia (conjugated and unconjugated). It is crucial to interpret these commonly ordered tests accurately as appropriate further workup, treatment and referral can greatly benefit the patient due to prompt treatment which can improve the natural history of several of the diseases mentioned and possibly reduce the risk of progression to the liver cirrhosis.

The emerging role of proteases in α1-antitrypsin deficiency and beyond

α1-Antitrypsin deficiency (AATD) has been historically under-recognised and under-diagnosed; recently it has begun to receive greater interest in terms of attempts at deeper elucidation of pathology and treatment options. However, the concept of disease phenotypes within AATD (emphysema, chronic bronchitis, bronchiectasis or a combination of phenotypes) has not been proposed or studied. Of the three neutrophil serine proteases, neutrophil elastase was historically believed to be the sole contributor to disease pathology in AATD. Recently, Proteinase-3 has been increasingly studied as an equal, if not greater, contributor to the disease process. Cathepsin G, however, has not been extensively evaluated in this area. Matrix metalloproteinases have also been mentioned in the pathogenesis of AATD but have not been widely explored. This article considers the available evidence for differential protease activity in patients with AATD, including the contribution to distinct phenotypes of the disease. Owing to limited literature in this area, extrapolations from studies of other chronic lung diseases with similar phenotypes, including COPD and bronchiectasis, have been made. We consider a new framework of understanding defined by protease-driven endotypes of disease which may lead to new opportunities for precision medicine.

The spectrum of clinical sequelae associated with alpha-1 antitrypsin deficiency

Alpha-1 antitrypsin (AAT) deficiency (AATD) is an autosomal co-dominant condition that predisposes to the development of lung disease, primarily emphysema. Emphysema results from the breakdown of lung matrix elastin by proteases, including neutrophil elastase, a protease normally inhibited by AAT. AATD also predisposes to liver (cirrhosis) and skin (panniculitis) disease, and to vasculitis. The prevalence of AATD is estimated to be approximately 1 in 3,500 individuals in the United States. However, lack of awareness of AATD among some physicians, misperceptions regarding the absence of effective therapy, and the close overlap in symptoms with asthma and non-AATD chronic obstructive pulmonary disease are thought to contribute to under-recognition of the disease. In patients with AATD, treatment with intravenous AAT augmentation therapy is the only currently available treatment known to slow the progression of emphysema. Moreover, smoking cessation and other lifestyle interventions also help improve outcomes. Early diagnosis and intervention are of key importance due to the irreversible nature of the resultant emphysema. Liver disease is the second leading cause of death among patients with AATD and a minority of patients present with panniculitis or antineutrophil cytoplasmic antibody-associated vasculitis, thought to be directly related to AATD. Though no randomized trial has assessed the effectiveness of augmentation therapy for AATD-associated panniculitis, clinical experience and case series suggest there is a benefit. Other diseases putatively linked to AATD include aneurysmal disease and multiple neurological conditions, although these associations remain speculative in nature.

Alpha-1 Antitrypsin Deficiency-Associated Clinical Manifestations and Healthcare Resource Use in the United States

Pulmonary events (PEs) associated with alpha-1 antitrypsin deficiency (AATD) can have a severe clinical course and increase healthcare resource use (HRU). However, AATD-associated HRU and healthcare costs have not been extensively described. This study describes and compares real-world HRU and healthcare costs among US patients with severe (requiring hospitalization after AATD-related PE) versus nonsevere AATD clinical course. Administrative healthcare claims for patients with a second primary AATD diagnosis between 6/1/2008 and 12/31/2017 were analyzed from 2 databases (requiring continuous enrollment 6 months preceding diagnosis). Patient baseline characteristics and AATD-associated PE incidence rates, HRU, and healthcare costs during follow-up were compared in patients with severe versus nonsevere AATD. Of 5109 patients with a second AATD diagnosis, 2674 (severe, n = 711 [26.6%]; nonsevere, n = 1963 [73.4%]) had ≥1 AATD-associated PE. PE incidence per 100 person-years was higher in patients with severe versus nonsevere AATD. Annual incidences (mean ± SD) of emergency department (1.2 ± 5.7 vs. 0.4 ± 1.2), inpatient (1.3 ± 2.5 vs. 0.1 ± 0.5), and outpatient (10.3 ± 15.9 vs. 5.7 ± 13.2) visits were higher in patients with severe versus nonsevere AATD. Median (interquartile range) annual costs were also higher for patients with severe versus nonsevere AATD for emergency department ($185 [$0-$1665] vs. $0 [$0-$264]), inpatient ($16,038 [$2968-$70,941] vs. $0 [$0-$0]), and outpatient ($2663 [$412-$10,277] vs. $1114 [$134-$4195]) visits. Higher percentages of patients with severe AATD were prescribed augmentation therapy, antibiotics, or corticosteroids. These findings suggest that patients with severe AATD have higher incidence of AATD-associated PEs, as well as higher HRU and healthcare costs.

Improving Screening for Alpha-1 Antitrypsin Deficiency with Direct Testing in the Pulmonary Function Testing Laboratory

Alpha-1 antitrypsin deficiency (AATD) is a common but highly underdiagnosed genetic disorder that may lead to chronic obstructive pulmonary disease (COPD), bronchiectasis, and liver disease. Early diagnosis is key to altering the course of disease as well as informing family members of potential risk. This randomized, prospective observational study compares the different testing modalities for AATD testing of at-risk patients initiated in the pulmonary function testing (PFT) laboratory. Providing a recommendation with a prescription for serologic testing, providing a finger-stick testing method (AlphaKit), and providing a buccal swab testing method (AlphaID) were compared to the community standard of referring the patient back to the PFT-ordering provider only. Results show that testing directly in the PFT laboratory has an odds ratio (OR) for completing testing of 35.14 (5.33 - 999.99), p-value of <0.0001, for buccal swab testing and an OR of 17.09 (2.58 - 729.99), p-value of 0.0002, for finger-stick testing compared to the community standard. Providing a prescription was no better than referral back to the PFT-ordering provider with an OR of 2.61(0.33 - 119.36), p-value of 0.6412. Resources needed to have testing performed by the Respiratory Therapy department were minimal with an average time of 1 to 5 minutes per patient tested. Causes of testing refusal were also identified. In conclusion, direct testing for AATD by respiratory therapists at the conclusion of PFT testing shows a significant improvement in rates of testing, especially with testing that utilizes buccal swab sample collection.

Pleiotropic associations of heterozygosity for the SERPINA1 Z allele in the UK Biobank

Homozygosity for the SERPINA1 Z allele causes α1-antitrypsin deficiency, a rare condition that can cause lung and liver disease. However, the effects of Z allele heterozygosity on nonrespiratory phenotypes, and on lung function in the general population, remain unclear. We conducted a large, population-based study to determine Z allele effects on >2400 phenotypes in the UK Biobank (N=303 353). Z allele heterozygosity was strongly associated with increased height (β=1.02 cm, p=3.91×10-68), and with other nonrespiratory phenotypes including increased risk of gall bladder disease, reduced risk of heart disease and lower blood pressure, reduced risk of osteoarthritis and reduced bone mineral density, increased risk of headache and enlarged prostate, as well as with blood biomarkers of liver function. Heterozygosity was associated with higher height-adjusted forced expiratory volume in 1 s (FEV1) (β=19.36 mL, p=9.21×10-4) and FEV1/forced vital capacity (β=0.0031, p=1.22×10-5) in nonsmokers, whereas in smokers, this protective effect was abolished. Furthermore, we show for the first time that sex modifies the association of the Z allele on lung function. We conclude that Z allele heterozygosity and homozygosity exhibit opposing effects on lung function in the UK population, and that these associations are modified by smoking and sex. In exploratory analyses, heterozygosity for the Z allele also showed pleiotropic associations with nonrespiratory health-related traits and disease risk.

Liquid Chromatography-Tandem Mass Spectrometry-Based α1-Antitrypsin (AAT) Testing

OBJECTIVES

Failure to produce sufficient quantities of functional α1-antitrypsin (AAT) can result in AAT deficiency (AATD) and significant comorbidities. Laboratory testing plays a vital role in AATD, with diagnosis requiring documentation of both a low AAT level and a mutated allele. This retrospective evaluation examines the efficacy of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) (proteotyping)-based algorithm for AATD detection.

METHODS

A 16-month retrospective data analysis was performed on two cohorts: 5,474 samples tested with the proteotype-based algorithm and 16,147 samples directly tested by isoelectric focusing (IEF) phenotyping.

RESULTS

LC-MS/MS reduced the rate of IEF testing by 97%. The 3% of cases reflexed to IEF resulted in 12 (0.2%) additional phenotype findings. Retrospectively applying the proteotype-based algorithm to the IEF cohort demonstrated a 99.9% sensitivity for the detection of deficiency-associated phenotypes. Most deficiency phenotypes missed by the proteotyping algorithm would come from heterozygous patients with an F, I, or P paired to an S or Z. In all of these cases, patient AAT levels were greater than 70 mg/dL, above the threshold for AAT augmentation therapy.

CONCLUSIONS

The proteotype algorithm is a sensitive and cost-effective approach for the diagnosis of clinical AAT deficiency.

Comorbidity Associations with AATD Among Commercially Insured and Medicare Beneficiaries with COPD in the US

Introduction

Alpha-1 antitrypsin deficiency (AATD) is often not identified in patients with chronic obstructive pulmonary disease (COPD) until advanced stages of disease, despite the availability of genetic testing. While clinical practice guidelines provide recommendations on patients who should be tested, more refined algorithms are needed to identify COPD patients who are likely candidates for AATD testing and to prevent delays in diagnosis and treatment. The objective of this study was to identify comorbid associations with AATD among patients diagnosed with COPD in the United States.

Methods

Using data from the 2012–2017 PharMetrics Plus Administrative Claims Database and 2011–2014 Medicare Fee for Service 5% Sample, patients with COPD (ICD-9-CM: 491.xx, 492.xx, or 496, ICD-10-CM J41, J42, J43, J44) and AATD (ICD-9-CM: 273.4, ICD-10-CM: E88.01) were identified. Patient demographic and diagnostic characteristics were assessed. Logistic regression models were developed to identify significant predictors of AATD.

Results

A cohort of 344,528 Medicare beneficiaries with COPD (of which 302 (0.09%) also had two diagnoses of AATD) and a cohort of 340,259 commercially insured patients with COPD (of which 1076 (0.3%) also had a diagnosis of AATD) were constructed. Associations with AATD identified in both models included ICD-9-CM and ICD-10-CM codes for chronic pulmonary heart disease, chronic liver disease and cirrhosis, and liver transplant.

Discussion

Significant associations with a diagnosis of AATD among patients with COPD were consistently represented in each of the datasets evaluated, which suggests meaningful comorbidity implications in AATD patients. These findings reinforce the need to test individuals with COPD for AATD as early as possible to help reduce the development of associated comorbid conditions.

Detection of alpha-1 antitrypsin deficiency: the past, present and future

Background

Most patients with alpha-1 antitrypsin deficiency remain undiagnosed and therefore do not benefit from current therapies or become eligible for research studies of new treatments under development. Improving the detection rate for AATD is therefore a high priority for the Alpha-1 Foundation. A workshop was held on June 23, 2019 in Orlando, Florida during which stakeholders from the research, pharmaceutical, and patient communities focused on the topic of alpha-1 antitrypsin deficiency detection.

Results

A variety of detection strategies have been explored in the past and new approaches are emerging as technology advances. Targeted detection includes patients with chronic obstructive pulmonary disease, unexplained chronic liver disease, and family members of affected individuals. Newborn screening, electronic medical record data mining, and direct-to-consumer testing remain options for future detection strategies.

Conclusion

These meeting proceedings can serve as a basis for innovative approaches to the detection of alpha-1 antitrypsin deficiency.

"Let my liver rather heat with wine" - a review of hepatic fibrosis pathophysiology and emerging therapeutics

Cirrhosis is characterized by extensive hepatic fibrosis, and it is the 14th leading cause of death worldwide. Numerous contributing conditions have been implicated in its development, including infectious etiologies, medication overdose or adverse effects, ingestible toxins, autoimmunity, hemochromatosis, Wilson’s disease and primary biliary cholangitis to list a few. It is associated with portal hypertension and its stigmata (varices, ascites, hepatic encephalopathy, combined coagulopathy and thrombophilia), and it is a major risk factor for hepatocellular carcinoma. Currently, orthotopic liver transplantation has been the only curative modality to treat cirrhosis, and the scarcity of donors results in many people waiting years for a transplant. Identification of novel targets for pharmacologic therapy through elucidation of key mechanistic components to induce fibrosis reversal is the subject of intense research. Development of robust models of hepatic fibrosis to faithfully characterize the interplay between activated hepatic stellate cells (the principal fibrogenic contributor to fibrosis initiation and perpetuation), hepatocytes and extracellular matrix components has the potential to identify critical components and mechanisms that can be exploited for targeted treatment. In this review, we will highlight key cellular pathways involved in the pathophysiology of fibrosis from extracellular ligands, effectors and receptors, to nuclear receptors, epigenetic mechanisms, energy homeostasis and cytokines. Further, molecular pathways of hepatic stellate cell deactivation are discussed, including apoptosis, senescence and reversal or transdifferentiation to an inactivated state resembling quiescence. Lastly, clinical evidence of fibrosis reversal induced by biologics and small molecules is summarized, current compounds under clinical trials are described and efforts for treatment of hepatic fibrosis with mesenchymal stem cells are highlighted. An enhanced understanding of the rich tapestry of cellular processes identified in the initiation, perpetuation and resolution of hepatic fibrosis, driven principally through phenotypic switching of hepatic stellate cells, should lead to a breakthrough in potential therapeutic modalities.

Identifying Alpha-1 Antitrypsin Deficiency Based on Computed Tomography Evidence of Emphysema

Introduction

Chronic obstructive pulmonary disease (COPD) is most commonly caused by smoking tobacco or cigarettes. However, alpha-1 antitrypsin deficiency (AATD) is the only genetic disorder known to cause COPD and these patients often present with emphysema earlier in life and with more severe disease. Additionally, AATD patients are often misdiagnosed with other lung disorders, and the diagnosis is often delayed for up to a decade. Furthermore, several clinicians may see the patient before genetic testing is performed and an official diagnosis is made. We hypothesized that patients with radiographic emphysema on computed tomography (CT) scan of the chest would represent an enriched population of patients with a higher prevalence of alpha-1 antitrypsin (AAT) carrier or heterozygous state.

Methods

We evaluated 250 in-patients with chest computed tomography (CT) findings of emphysema, and per clinical guidelines, all were tested for AAT with Alphakit finger stick blood collection kits. Sampling 250 patients provided power to detect a carrier prevalence of 20% +/- 1.0%.

Results

A total of 250 patients were recruited of which 53% were male, 91% Caucasian, 7% African American, and 16% active smokers. They smoked an average of 39 packs per year. The prevalence of carrier status (Pi*MS or Pi*MZ) was 6.8% (95% CI (4%, 11%)). The mean forced expiratory volume in one second (FEV-1) was 53%, predicted among Pi*MM patients (n=126) and not significantly different from the Pi*MS group (50%, n=13). 69% of Pi*MM were diagnosed with asthma or COPD, vs. 79% of Pi*MS (n=14) and 100% Pi*MZ (n=3), but the difference was not significant (p=0.4).

Conclusion

In the population studied, compared to a cohort of patients with abnormal pulmonary function tests (PFTs), radiographically evident emphysema did not identify patients at higher risk of being heterozygous or homozygous for AAT deficiency.

Advances in managing COPD related to α1 -antitrypsin deficiency: An under-recognized genetic disorder

α1 -Antitrypsin deficiency (AATD) predisposes individuals to chronic obstructive pulmonary disease (COPD) and liver disease. Despite being commonly described as rare, AATD is under-recognized, with less than 10% of cases identified. The following is a comprehensive review of AATD, primarily for physicians who treat COPD or asthma, covering the genetics, epidemiology, clinical presentation, screening and diagnosis, and treatments of AATD. For patients presenting with liver and/or lung disease, screening and diagnostic tests are the only methods to determine whether the disease is related to AATD. Screening guidelines have been established by organizations such as the World Health Organization, European Respiratory Society, and American Thoracic Society. High-risk groups, including individuals with COPD, nonresponsive asthma, bronchiectasis of unknown etiology, or unexplained liver disease, should be tested for AATD. Current treatment options include augmentation therapy with purified AAT for patients with deficient AAT levels and significant lung disease. Recent trial data suggest that lung tissue is preserved by augmentation therapy, and different dosing schedules are currently being investigated. Effective management of AATD and related diseases also includes aggressive avoidance of smoking and biomass burning, vaccinations, antibiotics, exercise, good diet, COPD medications, and serial assessment.

Alpha 1 antitrypsin to treat lung disease in alpha 1 antitrypsin deficiency: recent developments and clinical implications

Alpha 1 antitrypsin deficiency is a hereditary condition characterized by low alpha 1 proteinase inhibitor (also known as alpha 1 antitrypsin [AAT]) serum levels. Reduced levels of AAT allow abnormal degradation of lung tissue, which may ultimately lead to the development of early-onset emphysema. Intravenous infusion of AAT is the only therapeutic option that can be used to maintain levels above the protective threshold. Based on its biochemical efficacy, AAT replacement therapy was approved by the US Food and Drug administration in 1987. However, there remained considerable interest in selecting appropriate outcome measures that could confirm clinical efficacy in a randomized controlled trial setting. Using computed tomography as the primary measure of decline in lung density, the capacity for intravenously administered AAT replacement therapy to slow and modify the course of disease progression was demonstrated for the first time in the Randomized, Placebo-controlled Trial of Augmentation Therapy in Alpha-1 Proteinase Inhibitor Deficiency (RAPID) trial. Following these results, an expert review forum was held at the European Respiratory Society to discuss the findings of the RAPID trial program and how they may change the landscape of alpha 1 antitrypsin emphysema treatment. This review summarizes the results of the RAPID program and the implications for clinical considerations with respect to diagnosis, treatment and management of emphysema due to alpha 1 antitrypsin deficiency.

Diagnosing alpha-1 antitrypsin deficiency: the first step in precision medicine

Severe alpha-1 antitrypsin (AAT) deficiency is one of the most common serious genetic diseases in adults of European descent. Individuals with AAT deficiency have a greatly increased risk for emphysema and liver disease. Other manifestations include bronchiectasis, necrotizing panniculitis and granulomatosis with polyangiitis. Despite the frequency and potential severity, AAT deficiency remains under-recognized, and there is often a delay in diagnosis. This review will focus on three recent updates that should serve to encourage testing and diagnosis of AAT deficiency: first, the publication of a randomized clinical trial demonstrating the efficacy of intravenous augmentation therapy in slowing the progression of emphysema in AAT deficiency; second, the mounting evidence showing an increased risk of lung disease in heterozygous PI MZ genotype carriers; last, the recent publication of a clinical practice guideline, outlining diagnosis and management. Though it has been recognized for more than fifty years, AAT deficiency exemplifies the modern paradigm of precision medicine, with a diagnostic test that identifies a genetic subtype of a heterogeneous disease, leading to a targeted treatment.

Liver Transplantation in Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin (AAT) deficiency is a common inherited metabolic disorder caused by a point mutation in the SERPIN1A gene. A small portion of homozygous PI*ZZ individuals develop severe liver disease that requires liver transplantation. Posttransplant survival is excellent. The largest burden of advanced liver disease lies within the adult population rather than children. Evaluation of lung function in adults before transplant is essential because of the underlying risk for chronic obstructive pulmonary disease. Post-liver transplantation lung function should also be monitored for decline. Although uncommon, cases of simultaneous lung and liver transplant for AAT deficiency have been reported.

Alpha-1 antitrypsin Pi*Z gene frequency and Pi*ZZ genotype numbers worldwide: an update

In alpha-1 antitrypsin deficiency (AATD), the Z allele is present in 98% of cases with severe disease, and knowledge of the frequency of this allele is essential from a public health perspective. However, there is a remarkable lack of epidemiological data on AATD worldwide, and many of the data currently used are outdated. Therefore, the objective of this study was to update the knowledge of the frequency of the Z allele to achieve accurate estimates of the prevalence and number of Pi*ZZ genotypes worldwide based on studies performed according to the following criteria: 1) samples representative of the general population, 2) AAT phenotyping characterized by adequate methods, and 3) measurements performed using a coefficient of variation calculated from the sample size and 95% confidence intervals. Studies fulfilling these criteria were used to develop maps with an inverse distance weighted (IDW)-interpolation method, providing numerical and graphical information of Pi*Z distribution worldwide. A total of 224 cohorts from 65 countries were included in the study. With the data provided by these cohorts, a total of 253,404 Pi*ZZ were estimated worldwide: 119,594 in Europe, 91,490 in America and Caribbean, 3,824 in Africa, 32,154 in Asia, 4,126 in Australia, and 2,216 in New Zealand. In addition, the IDW-interpolation maps predicted Pi*Z frequencies throughout the world even in some areas that lack real data. In conclusion, the inclusion of new well-designed studies and the exclusion of the low-quality ones have significantly improved the reliability of results, which may be useful to plan strategies for future research and diagnosis and to rationalize the therapeutic resources available.

Extensive testing or focused testing of patients with elevated liver enzymes

BACKGROUND & AIMS

Many patients have elevated serum aminotransferases reflecting many underlying conditions, both common and rare. Clinicians generally apply one of two evaluative strategies: testing for all diseases at once (extensive) or just common diseases first (focused).

METHODS

We simulated the evaluation of 10,000 adult outpatients with elevated with alanine aminotransferase to compare both testing strategies. Model inputs employed population-based data from the US (National Health and Nutrition Examination Survey) and Britain (Birmingham and Lambeth Liver Evaluation Testing Strategies). Patients were followed until a diagnosis was provided or a diagnostic liver biopsy was considered. The primary outcome was US dollars per diagnosis. Secondary outcomes included doctor visits per diagnosis, false-positives per diagnosis and confirmatory liver biopsies ordered.

RESULTS

The extensive testing strategy required the lowest monetary cost, yielding diagnoses for 54% of patients at $448/patient compared to 53% for $502 under the focused strategy. The extensive strategy also required fewer doctor visits (1.35 vs. 1.61 visits/patient). However, the focused strategy generated fewer false-positives (0.1 vs. 0.19/patient) and more biopsies (0.04 vs. 0.08/patient). Focused testing becomes the most cost-effective strategy when accounting for pre-test probabilities and prior evaluations performed. This includes when the respective prevalence of alcoholic, non-alcoholic and drug-induced liver disease exceeds 51.1%, 53.0% and 13.0%. Focused testing is also the most cost-effective strategy in the referral setting where assessments for viral hepatitis, alcoholic and non-alcoholic fatty liver disease have already been performed.

CONCLUSIONS

Testing for elevated liver enzymes should be deliberate and focused to account for pre-test probabilities if possible.

LAY SUMMARY

Many patients have elevated liver enzymes reflecting one of many possible liver diseases, some of which are very common and some of which are rare. Tests are widely available for most causes but it is unclear whether clinicians should order them all at once or direct testing based on how likely a given disease may be given the patient's history and physical exam. The tradeoffs of both approaches involve the money spent on testing, number of office visits needed, and false positive results generated. This study shows that if there are no clues available at the time of evaluation, testing all at once saves time and money while causing more false positives. However, if there are strong clues regarding the likelihood of a particular disease, limited testing saves time, money and prevents false positives.

Pathophysiology of Alpha-1 Antitrypsin Lung Disease

Alpha-1 antitrypsin deficiency (AATD) is an inherited disorder characterized by low serum levels of alpha-1 antitrypsin (AAT). Loss of AAT disrupts the protease-antiprotease balance in the lungs, allowing proteases, specifically neutrophil elastase, to act uninhibited and destroy lung matrix and alveolar structures. Destruction of these lung structures classically leads to an increased risk of developing emphysema and chronic obstructive pulmonary disease (COPD), especially in individuals with a smoking history. It is estimated that 3.4 million people worldwide have AATD. However, AATD is considered to be significantly underdiagnosed and underrecognized by clinicians. Contributing factors to the diagnostic delay of approximately 5.6 years are: inadequate awareness by healthcare providers, failure to implement recommendations from the American Thoracic Society/European Respiratory Society, and the belief that AATD testing is not warranted. Diagnosis can be attained using qualitative or quantitative laboratory testing. The only FDA approved treatment for AATD is augmentation therapy, although classically symptoms have been treated similarly to those of COPD. Future goals of AATD treatment are to use gene therapy using vector systems to produce therapeutic levels of AAT in the lungs without causing a systemic inflammatory response.

Recent advances in understanding and treating COPD related to α1-antitrypsin deficiency

INTRODUCTION

Alpha-1-antitrypsin deficiency (AATD) is an orphan disease that predisposes individuals to COPD and liver disease. The following is a comprehensive review of AATD from epidemiology to treatment for physicians who treat COPD or asthma. Areas covered: In this comprehensive review of alpha-1-antitrypsin deficiency, we describe the historical perspective, genetics, epidemiology, clinical presentation and symptoms, screening and diagnosis, and treatments of the condition. Expert commentary: The two most important directions for advancing the understanding of AATD involve improving detection of the condition, especially in asymptomatic patients, and advancing knowledge of treatments directed specifically at AATD-related conditions. With regard to treatment for AATD-related conditions, research must continue to explore the implications and importance of augmentation therapy as well as consider new implementations that may prove more successful taking into consideration not only factors of pulmonary function and liver health, but also product availability and financial viability.

Trials and Tribulations: An Industry Perspective on Conducting Registrational Trials in Alpha-1 Antitrypsin Deficiency

Registrational trials in rare and orphan diseases present complexities related to the identification of subjects, recruitment, logistical hurdles incumbent with far-flung study sites, and end points that are often less well defined than are those used in more common illnesses. Alpha-1 antitrypsin deficiency is an orphan disease of genetic origin that carries the additional challenges of variable penetration and slow disease progression. Registrational trials of augmentation therapy using plasma-derived alpha-1 antitrypsin carry all of the above-noted burdens, as well as competition from commercially available augmentation therapy in many countries.

α1-Antitrypsin deficiency

α1-Antitrypsin deficiency (A1ATD) is an inherited disorder caused by mutations in SERPINA1, leading to liver and lung disease. It is not a rare disorder but frequently goes underdiagnosed or misdiagnosed as asthma, chronic obstructive pulmonary disease (COPD) or cryptogenic liver disease. The most frequent disease-associated mutations include the S allele and the Z allele of SERPINA1, which lead to the accumulation of misfolded α1-antitrypsin in hepatocytes, endoplasmic reticulum stress, low circulating levels of α1-antitrypsin and liver disease. Currently, there is no cure for severe liver disease and the only management option is liver transplantation when liver failure is life-threatening. A1ATD-associated lung disease predominately occurs in adults and is caused principally by inadequate protease inhibition. Treatment of A1ATD-associated lung disease includes standard therapies that are also used for the treatment of COPD, in addition to the use of augmentation therapy (that is, infusions of human plasma-derived, purified α1-antitrypsin). New therapies that target the misfolded α1-antitrypsin or attempt to correct the underlying genetic mutation are currently under development.

Multilineage transduction of resident lung cells in vivo by AAV2/8 for α1-antitrypsin gene therapy

In vivo gene delivery has long represented an appealing potential treatment approach for monogenic diseases such as α1-antitrypsin deficiency (AATD) but has proven challenging to achieve in practice. Alternate pseudotyping of recombinant adeno-associated virus (AAV) vectors is producing vectors with increasingly heterogeneous tropic specificity, giving researchers the ability to target numerous end-organs affected by disease. Herein, we describe sustained pulmonary transgene expression for at least 52 weeks after a single intratracheal instillation of AAV2/8 and characterize the multiple cell types transduced within the lung utilizing this approach. We demonstrate that lung-directed AAV2/8 is able to achieve therapeutic α-1 antitrypsin (AAT) protein levels within the lung epithelial lining fluid and that AAT gene delivery ameliorates the severity of experimental emphysema in mice. We find that AAV2/8 efficiently transduces hepatocytes in vivo after intratracheal administration, a finding that may have significance for AAV-based human gene therapy studies. These results support direct transgene delivery to the lung as a potential alternative approach to achieve the goal of developing a gene therapy for AATD.

α1-Antitrypsin Deficiency

α1-Antitrypsin deficiency is an autosomal codominant condition that predisposes to emphysema and cirrhosis. The condition is common but grossly under-recognized. Identifying patients' α1-antitrypsin deficiency has important management implications (ie, smoking cessation, genetic and occupational counseling, and specific treatment with the infusion of pooled human plasma α1-antitrypsin). The weight of evidence suggests that augmentation therapy slows the progression of emphysema in individuals with severe α1-antitrypsin deficiency.

The Diagnosis and Management of Alpha-1 Antitrypsin Deficiency in the Adult

Background: The diagnosis and clinical management of adults with alpha-1 antitrypsin deficiency (AATD) have been the subject of ongoing debate, ever since the publication of the first American Thoracic Society guideline statement in 1989.¹ In 2003, the "American Thoracic Society (ATS)/European Respiratory Society (ERS) Statement: Standards for the Diagnosis and Management of Individuals with Alpha-1 Antitrypsin Deficiency" made a series of evidence-based recommendations, including a strong recommendation for broad-based diagnostic testing of all symptomatic adults with chronic obstructive pulmonary disease (COPD).² Even so, AATD remains widely under-recognized. To update the 2003 systematic review and clinical guidance, the Alpha-1 Foundation sponsored a committee of experts to examine all relevant, recent literature in order to provide concise recommendations for the diagnosis and management of individuals with AATD. Purpose: To provide recommendations for: (1) the performance and interpretation of diagnostic testing for AATD, and (2) the current management of adults with AATD and its associated medical conditions. Methods: A systematic review addressing the most pressing questions asked by clinicians (clinician-centric) was performed to identify citations related to AATD that were published since the 2003 comprehensive review, specifically evaluating publications between January 2002 and December 2014. Important, more recent publications were solicited from the writing committee members as well. The combined comprehensive literature reviews of the 2003 document and this current review comprise the evidence upon which the committee's conclusions and recommendations are based. Results: Recommendations for the diagnosis and management of AATD were formulated by the committee. Conclusions: The major recommendations continue to endorse and reinforce the importance of testing for AATD in all adults with symptomatic fixed airflow obstruction, whether clinically labeled as COPD or asthma. Individuals with unexplained bronchiectasis or liver disease also should be tested. Family testing of first-degree relatives is currently the most efficient detection technique. In general, individuals with AATD and emphysema, bronchiectasis, and/or liver disease should be managed according to usual guidelines for these clinical conditions. In countries where intravenous augmentation therapy with purified pooled human plasma-derived alpha-1 antitrypsin is available, recent evidence now provides strong support for its use in appropriate individuals with lung disease due to AATD.

Deficiency Mutations of Alpha-1 Antitrypsin. Effects on Folding, Function, and Polymerization

Misfolding, polymerization, and defective secretion of functional alpha-1 antitrypsin underlies the predisposition to severe liver and lung disease in alpha-1 antitrypsin deficiency. We have identified a novel (Ala336Pro, Baghdad) deficiency variant and characterized it relative to the wild-type (M) and Glu342Lys (Z) alleles. The index case is a homozygous individual of consanguineous parentage, with levels of circulating alpha-1 antitrypsin in the moderate deficiency range, but is a biochemical phenotype that could not be classified by standard methods. The majority of the protein was present as functionally inactive polymer, and the remaining monomer was 37% active relative to the wild-type protein. These factors combined indicate an 85 to 95% functional deficiency, similar to that seen with ZZ homozygotes. Biochemical, biophysical, and computational studies further defined the molecular basis of this deficiency. These studies demonstrated that native Ala336Pro alpha-1 antitrypsin could populate the polymerogenic intermediate-and therefore polymerize-more readily than either wild-type alpha-1 antitrypsin or the Z variant. In contrast, folding was far less impaired in Ala336Pro alpha-1 antitrypsin than in the Z variant. The data are consistent with a disparate contribution by the "breach" region and "shutter" region of strand 5A to folding and polymerization mechanisms. Moreover, the findings demonstrate that, in these variants, folding efficiency does not correlate directly with the tendency to polymerize in vitro or in vivo. They therefore differentiate generalized misfolding from polymerization tendencies in missense variants of alpha-1 antitrypsin. Clinically, they further support the need to quantify loss-of-function in alpha-1 antitrypsin deficiency to individualize patient care.

Alpha-1-antitrypsin deficiency: increasing awareness and improving diagnosis

Alpha-1-antitrypsin deficiency (AATD) is a hereditary disorder that is characterized by a low serum level of alpha-1-antitrypsin (AAT). The loss of anti-inflammatory and antiproteolytic functions, together with pro-inflammatory effects of polymerized AAT contribute to protein degradation and increased inflammation resulting in an increased risk of developing chronic obstructive pulmonary disease (COPD) and emphysema, especially in smokers. AATD is a rare disease that is significantly underdiagnosed. According to recent data that are based on extrapolations, in many countries only 5-15% of homozygous individuals have been identified. Furthermore, the diagnostic delay typically exceeds 5 years, resulting in an average age at diagnosis of about 45 years. Although the American Thoracic Society/European Respiratory Society recommendations state that all symptomatic adults with persistent airway obstruction should be screened, these recommendations are not being followed. Potential reasons for that include missing knowledge about the disease and the appropriate tests, and the low awareness of physicians with regard to the disorder. Once the decision to initiate testing has been made, a screening test (AAT serum level or other) should be performed. Further diagnostic evaluation is based on the following techniques: polymerase chain reaction (PCR) for frequent and clinically important mutations, isoelectric focusing (IEF) with or without immunoblotting, and sequencing of the gene locus coding for AAT. Various diagnostic algorithms have been published for AATD detection (severe deficiency or carrier status). Modern laboratory approaches like the use of serum separator cards, a lateral flow assay to detect the Z-protein, and a broader availability of next-generation sequencing are recent advances, likely to alter existing algorithms.

Current and Future Burden of Chronic Nonmalignant Liver Disease

Disease burden is an important indicator of the state of health of a population. It can be measured as the frequency (eg, incidence and prevalence) of a condition or its effects including fatal and non-fatal health loss from disease (eg, disability-adjusted life years) as well as the financial costs (eg, direct healthcare costs and indirect healthcare expenditures related to lost income because of premature death). Accurate disease burden information is essential for policy-making such as prioritization of health interventions and allocation of resources. Chronic liver disease (CLD) causes substantial health and economic burden in the United States, where nearly 2 million deaths annually are attributable to CLD. In the recent past, overall mortality rate of CLD has been increasing. Viral hepatitis and alcoholic liver disease are thought to be the most common etiologies of chronic liver diseases. More recently, the prevalence of nonalcoholic fatty liver disease is rapidly increasing, and nonalcoholic steatohepatitis has become a leading indication for liver transplantation. In this article, we assemble available data on the burden of CLD in the United States, focusing on nonmalignant complications, whereas the impact on mortality and healthcare expenses of hepatocellular carcinoma, an important consequence of CLD, is discussed elsewhere.

Alpha-1 antitrypsin deficiency and the risk of hepatocellular carcinoma in end-stage liver disease

AIM: To evaluate the association between alpha-1 antitrypsin deficiency (A1ATD) and hepatocellular carcinoma (HCC) in patients with end-stage liver disease (ESLD).

METHODS: Patients with cirrhosis and ESLD referred to the Cleveland Clinic Foundation for liver transplantation between 2003 and 2014 were included in the study (N = 675). ESLD was defined as having histological features of cirrhosis and/or radiological evidence of cirrhosis in the context of portal hypertension (ascites, variceal bleeding, thrombocytopenia, or hepatic encephalopathy). A1ATD was diagnosed using phenotype characterization (MZ or ZZ), liver biopsy detection of PAS-positive diastase-resistant (PAS+) globules, or both. Patients with other causes of liver diseases such as hepatitis C virus (HCV), alcoholic liver disease and non-alcoholic steatohepatitis (NASH) or NASH were also included in the study. HCC was diagnosed by using imaging modalities, biopsy findings, or explanted liver inspection. Follow-up time was defined as the number of years from the diagnosis of cirrhosis to the diagnosis of hepatocellular carcinoma, or from the diagnosis of cirrhosis to the last follow up visit. The rate of HCC was assessed using time-to-interval analysis for interval censored data.

RESULTS: This study included 675 patients. 7% of subjects had A1ATD (n = 47). Out of all subjects who did not have A1ATD, 46% had HCV, 17% had alcoholic liver disease, 19% had NASH and 18% had another primary diagnosis. Of the 47 subjects with A1ATD, 15 had a primary diagnosis of A1ATD (PI*ZZ phenotype and PAS+ globules), 8 had a PI*MZ phenotype alone, 14 had PAS+ alone, and 10 had both the PI*MZ phenotype and PAS+. Median follow-up time was 3.4 (25^th, 75^th percentiles: 1, 5.2) years. The overall rate of hepatocellular carcinoma in all subjects was 29% (n = 199). In the A1ATD group, the incidence rate of HCC was 8.5% compared to 31% in the group of patients with other causes of cirrhosis (P = 0.001). Patients with ESLD due to A1ATD had the lowest yearly cumulative rate of hepatocellular carcinoma at 0.88% per year compared to 2.7% for those with HCV cirrhosis, 1.5% in patients with NASH and 0.9% in alcohol-induced liver disease (P < 0.001).

CONCLUSION: Within this group of patients with ESLD, there was no significant association between A1ATD and increased risk of HCC.

Characteristics of Chronic Obstructive Pulmonary Disease (COPD) Patients Reporting Alpha-1 Antitrypsin Deficiency in the WebMD Lung Health Check Database

Objectives: This study compared characteristics of chronic obstructive pulmonary disease (COPD) among patients with and without alpha-1 antitrypsin deficiency (A1AD). Methods: Data from WebMD's Lung Disease Health Check was analyzed for participants who self-reported a COPD diagnosis (N=177,865) and whether or not they had an A1AD diagnosis (based on a positive response to the question "Do you have alpha-1 antitrypsin deficiency?"). We used regression modeling to determine the relation between A1AD status and demographic characteristics, symptoms, lung function, quality of life, comorbidities, and smoking habits. Results: Out of 177,865 participants who reported a COPD diagnosis, 1,619 (0.92%) also reported an A1AD diagnosis. When compared to the total COPD population, those with A1AD were less likely to be female (odds ratio [OR]=0.68, 95% confidence interval [CI] 0.61, 0.75) or current smokers (OR 0.72, 95% CI 0.62, 0.83), and more likely to know their lung function value (OR=3.44, 95% CI 3.07, 3.87). With regard to symptoms, those with A1AD were less likely to report wheezing (OR=0.82, 95% CI 0.75, 0.91) and chronic cough (OR=0.81, 95% CI 0.73, 0.89) and more likely to report tightness in the chest (OR= 1.19, 95% CI 1.08, 1.32). Overall, A1AD participants had a lower quality of life with a higher proportion reporting severe impairment in work life (OR=1.55, 95% CI 1.39, 1.7), home life (OR=1.40, 95% CI 1.26, 1.56), and personal relationships (OR=1.48, 95% CI 1.32, 1.65). Conclusions: COPD patients with A1AD report significantly worse quality of life relative to the non-A1AD COPD population.

Characteristics of Chronic Obstructive Pulmonary Disease (COPD) Patients Reporting Alpha-1 Antitrypsin Deficiency in the WebMD Lung Health Check Database

Objectives: This study compared characteristics of chronic obstructive pulmonary disease (COPD) among patients with and without alpha-1 antitrypsin deficiency (A1AD). Methods: Data from WebMD's Lung Disease Health Check was analyzed for participants who self-reported a COPD diagnosis (N=177,865) and whether or not they had an A1AD diagnosis (based on a positive response to the question "Do you have alpha-1 antitrypsin deficiency?"). We used regression modeling to determine the relation between A1AD status and demographic characteristics, symptoms, lung function, quality of life, comorbidities, and smoking habits. Results: Out of 177,865 participants who reported a COPD diagnosis, 1,619 (0.92%) also reported an A1AD diagnosis. When compared to the total COPD population, those with A1AD were less likely to be female (odds ratio [OR]=0.68, 95% confidence interval [CI] 0.61, 0.75) or current smokers (OR 0.72, 95% CI 0.62, 0.83), and more likely to know their lung function value (OR=3.44, 95% CI 3.07, 3.87). With regard to symptoms, those with A1AD were less likely to report wheezing (OR=0.82, 95% CI 0.75, 0.91) and chronic cough (OR=0.81, 95% CI 0.73, 0.89) and more likely to report tightness in the chest (OR= 1.19, 95% CI 1.08, 1.32). Overall, A1AD participants had a lower quality of life with a higher proportion reporting severe impairment in work life (OR=1.55, 95% CI 1.39, 1.7), home life (OR=1.40, 95% CI 1.26, 1.56), and personal relationships (OR=1.48, 95% CI 1.32, 1.65). Conclusions: COPD patients with A1AD report significantly worse quality of life relative to the non-A1AD COPD population.

α1 Antitrypsin deficiency: current best practice in testing and augmentation therapy

α1 Antitrypsin deficiency (AATD) increases the risk of chronic obstructive pulmonary disease (COPD), liver disease and other conditions. Although it is not a rare disease, it is a condition rarely diagnosed because of unawareness by most healthcare providers who manage subjects at risk. Testing recommendations have been published and strongly suggest testing all subjects with confirmed COPD, cryptogenic liver cirrhosis, subjects with incompletely reversible airflow obstruction and siblings of affected individuals. Testing strategies usually imply a combination of measures of α1 antitrypsin (AAT) levels, phenotyping and genotyping, techniques that have been facilitated for in-office use by development of testing kits using dried blood spots. Early detection of subjects is crucial to apply effective preventive measures and early institution of therapy. The only specific Food and Drug Administration - approved therapy for this condition is lifelong weekly intravenous AAT replacement (augmentation therapy). Observational studies strongly suggest a beneficial effect of augmentation therapy in slowing lung function decline and randomized trials suggest a beneficial effect in slowing the progression of emphysema over time as measured by computed tomography. In addition, augmentation therapy has been shown to modulate systemic inflammatory responses and affect markers of elastin degradation. As new markers of disease progression are discovered, new doses of AAT replacement are tested and sub-phenotypes of disease are described, treatment recommendations are likely to change towards a more individualized therapeutic approach.

Challenging identification of a novel PiISF and the rare PiMmaltonZ α1-antitrypsin deficiency variants in two patients

OBJECTIVES

α1-Antitrypsin (AAT) deficiency is associated with an increased risk for lung and liver disease. Identification of AAT deficiency as the underlying cause of these diseases is important in correct patient management.

METHODS

AAT deficiency is commonly diagnosed by demonstrating low concentrations of AAT followed by genotype and/or phenotype testing. However, this algorithm may miss novel AAT phenotypes.

RESULTS

We report two cases of AAT deficiency in two patients: a case of the novel phenotype PiISF, misclassified as PiII by phenotyping, and a case of the rare phenotype PiMmaltonZ misclassified as PiM2Z.

CONCLUSIONS

These cases highlight the importance of understanding the limitations of a commonly used diagnostic algorithm, use of further gene sequencing in applicable cases, and the potential for underdiagnosis of AAT deficiency in patients with chronic obstructive pulmonary disease.

The challenge of detecting alpha-1 antitrypsin deficiency

Alpha-1 antitrypsin deficiency (AATD) is relatively common but under-recognized. Indeed, fewer than 10% of the estimated 100,000 Americans with AATD have been diagnosed currently, with common reports of long delays between initial symptoms and first detection and the need to see multiple physicians before diagnosis. Because detection can confer benefits (e.g., identification of at-risk family members, lower smoking likelihood, consideration of augmentation therapy), targeted detection of AATD in at-risk groups such as all symptomatic adults with COPD has been endorsed. Two general approaches to detection have been studied: population-based screening (in which testing is performed in a group for whom no increased risk of having AATD exists) and targeted detection or case-finding (in which testing is confined to those with an attributable condition such as COPD or chronic liver disease). Studies to date have suggested that population-based screening is not cost-effective, whereas targeted detection of AATD has been advocated by official society guidelines. Efforts to enhance detection of AATD individuals have included various approaches, including educational campaigns, provision of free test kits, issuance of reminders with medical reports or within an electronic medical record, and empowering respiratory therapists to conduct testing for AATD in pulmonary function laboratories. Such programs have identified individuals with severe deficiency of alpha-1 antitrypsin in up to 12% of subjects, with considerable variation across series by testing criteria. Overall, the persistence of under-recognition of AATD underscores the need for continued efforts to optimize detection of this potentially debilitating genetic disease.

The endosomal protein-sorting receptor sortilin has a role in trafficking α-1 antitrypsin

Up to 1 in 3000 individuals in the United States have α-1 antitrypsin deficiency, and the most common cause of this disease is homozygosity for the antitrypsin-Z variant (ATZ). ATZ is inefficiently secreted, resulting in protein deficiency in the lungs and toxic polymer accumulation in the liver. However, only a subset of patients suffer from liver disease, suggesting that genetic factors predispose individuals to liver disease. To identify candidate factors, we developed a yeast ATZ expression system that recapitulates key features of the disease-causing protein. We then adapted this system to screen the yeast deletion mutant collection to identify conserved genes that affect ATZ secretion and thus may modify the risk for developing liver disease. The results of the screen and associated assays indicate that ATZ is degraded in the vacuole after being routed from the Golgi. In fact, one of the strongest hits from our screen was Vps10, which can serve as a receptor for the delivery of aberrant proteins to the vacuole. Because genome-wide association studies implicate the human Vps10 homolog, sortilin, in cardiovascular disease, and because hepatic cell lines that stably express wild-type or mutant sortilin were recently established, we examined whether ATZ levels and secretion are affected by sortilin. As hypothesized, sortilin function impacts the levels of secreted ATZ in mammalian cells. This study represents the first genome-wide screen for factors that modulate ATZ secretion and has led to the identification of a gene that may modify disease severity or presentation in individuals with ATZ-associated liver disease.

α1-Proteinase inhibitor (human) in the treatment of hereditary emphysema secondary to α1-antitrypsin deficiency: number and costs of years of life gained

BACKGROUND

α(1)-Antitrypsin deficiency (α-ATD) is a disorder inherited in an autosomal recessive pattern, with co-dominant alleles known as the protease inhibitor system (Pi). The main function of α(1)-antitrypsin (α-AT) is to protect the lungs against a powerful elastase released from neutrophil leucocytes. α-ATD typically presents with a serum α-AT level of <50 mg/dL. In severe α-ATD, phenotype PiZZ, protection of the lungs is compromised, leading to an accelerated decline in forced expiratory volume in 1 second (FEV(1)). As a result, a patient may develop pulmonary emphysema of the panacinar type at a young age (third to fourth decades of life), with cigarette smoking being the most significant additional risk factor. It has been shown that weekly or monthly infusion of human α-AT is effective in raising serum α-AT levels to desired levels (>80 mg/dL), with few, if any, adverse effects.

OBJECTIVE

The present study was designed to discern the number of years of life gained, and the expense per year of life gained, associated with use of α-AT augmentation therapy (α(1)-proteinase inhibitor [human]), relative to 'no therapeutic intervention' in persons with α-ATD.

METHODS

Monte Carlo simulation (MCS) was used to: (i) estimate the number of years of life gained; and (ii) estimate the health service expenditures per year of life gained for persons receiving, or not receiving, α-AT augmentation therapy. MCS afforded a decision-analytical framework parameterized with both stochastic (random) and deterministic (fixed) components, and yielded a fiscal risk-profile for each simulated cohort of interest (eight total: by sex, smoking status [non-smoker; or past use (smoker)]; and use of α-AT augmentation therapy). The stochastic components employed in the present inquiry were: (i) age-specific body weight, and height; (ii) age-specific mortality; and (iii) the probability distribution for receipt of a lung transplant, as a function of FEV(1). The deterministic components employed in the present inquiry were: (i) age in years for the simulated cohort; (ii) outlays for α-AT augmentation therapy; (iii) health service expenditures associated with receipt of a lung transplant; (iv) annual decline in FEV(1); (v) percent predicted FEV(1); (vi) initiation of α-AT augmentation therapy as a function of percent predicted FEV(1); (vii) need for a lung transplant as a function of percent predicted FEV(1); (viii) annual rate of lung infection; and (ix) mortality as a function of percent predicted FEV(1). Results are reported from a payer perspective ($US, year of costing 2010).

RESULTS

Receipt of α-AT augmentation therapy was associated with a significant increase (p < 0.05) in years of life gained, with female smokers gaining an estimated mean 7.14 years (cost per year: $US248 361 [95% CI 104 531, 392 190]); female non-smokers gained an estimated mean 9.19 years (cost per year: $US160 502 [95% CI 37 056, 283 947)]); male smokers gained an estimated mean 5.93 years (cost per year: $US142 250 [95% CI 48 467, 236 032]); and male non-smokers gained an estimated mean 10.60 years (cost per year: $US59 234 [95% CI 20 719, 97 548]).

CONCLUSION

Use of α-AT augmentation therapy was associated with an increase in years of life gained by sex and history of tobacco use, and at a cost per year of life gained comparable to that of other evidenced-based interventions.

Genes and chronic obstructive pulmonary disease

Although much remains to be done, recent advances and the advent of new methodologies are promising and should yield increased understanding of the genetic and epigenetic mechanisms influencing the pathogenesis of COPD, both related and unrelated to severe AAT deficiency. Such understanding should ultimately be translated into novel approaches to prevent, diagnose, and treat COPD.

A review of α1-antitrypsin deficiency

α(1)-Antitrypsin (AAT) deficiency is an underrecognized genetic condition that affects approximately 1 in 2,000 to 1 in 5,000 individuals and predisposes to liver disease and early-onset emphysema. AAT is mainly produced in the liver and functions to protect the lung against proteolytic damage (e.g., from neutrophil elastase). Among the approximately 120 variant alleles described to date, the Z allele is most commonly responsible for severe deficiency and disease. Z-type AAT molecules polymerize within the hepatocyte, precluding secretion into the blood and causing low serum AAT levels (∼ 3-7 μM with normal serum levels of 20-53 μM). A serum AAT level of 11 μM represents the protective threshold value below which the risk of emphysema is believed to increase. In addition to the usual treatments for emphysema, infusion of purified AAT from pooled human plasma-so-called "augmentation therapy"-represents a specific therapy for AAT deficiency and raises serum levels above the protective threshold. Although definitive evidence from randomized controlled trials of augmentation therapy is lacking and therapy is expensive, the available evidence suggests that this approach is safe and can slow the decline of lung function and emphysema progression. Promising novel therapies are under active investigation.